This invention relates generally to electrical connectors for use with high power radio frequency transmit systems. More specifically, this invention relates to connectors which provide corona protection and are quickly connectable and disconnectable.
Low frequency radio signals are easily distortable by naturally occurring background noise. For increased signal clarity, a large amount of power is required. In some radio transmit system applications, for example, high-voltages and power in the range of 50,000 to 3,000,000 watts are used.
High power radio frequency transmit systems are tuned to a desired frequency by the use of high-voltage helix coils, variometers and other tuning components. A helix tuning coil typically has a multitude of connection points along the length of the coil. By applying a voltage having desired signal to a selected connection point, the frequency of the radio transmit system can be varied or adjusted. Thus, various high-voltage connectors have been developed.
A typical high-voltage connector utilizes copper plates having six equally spaced nuts, bolts and lock washers spaced evenly near the perimeter of the plate to hold a connection together. On a large helix coil, these connection points can be awkwardly positioned, some over twenty-five feet above the floor. Various tools are required to change the connector. An operator may require as much as half of an hour to change an existing connection.
An additional problem stems from the fact that high voltage electricity has a tendency to arc, especially at pointed or abrupt connection points. Such arcing is technically named corona and is characterized by a blue luminous glow and crackling or hissing sounds. Corona discharges can damage surrounding equipment and cause significant power losses. It is, thus, desirable to prevent corona discharges from the area surrounding high-voltage connectors.
Technically, corona discharge from a high voltage connector occurs when the voltage gradient (voltage per unit area) reaches a critical value. Since the voltage gradient is dependent on the geometry of the connection, a connector having a relatively small area with sharp edges will more likely discharge corona than a connector having larger, curved geometry. No provision is made on existing connectors to control electric field gradients at of near the connectors to reduce the likelihood of arcing or corona.
With the present inventive concept, the foregoing limitations have been recognized to provide quick high-voltage connections and protection against corona. This concept, simply stated, includes employing a hand rotatable connector having a geometry which is designed to control electric field gradients near the connector to protect against corona discharge.